• Journal of Korean Society for Geospatial Information Science
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• v.1 no.2 s.2
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• pp.177-184
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• 1993

To obtain large scale precise geographical information in local area we determined external orientation parameters of camn exactly and conducted aerial photography using remote control airship loaded 35mm non-metric camera that produced systematic error coefficients. Ground control Points were determined by differential GPS. Therefore we can try to improve accuracy and economical efficiency. Also, it is suggested that remote control airship photogrammetry can be applied to make large scale topographic map using analytical plotter as calibrated accuracy.

• Proceedings of the KIEE Conference
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• 1997.07c
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• pp.822-824
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• 1997

The routing and surveying a transmission line should be done in advance of its construction. It is getting more difficult to construct transmission line day by day, due to the rapid increase of people's demand resulting from the recent change of social environment and people's consciousness. In order to solve these complicated conditions actively and rationally, it is necessary to be more scientific, objective and computerizable for the routing and surveying of a transmission line. New technologies on routing and surveying a 765kV transmission line are remote sensing, Global Positioning System and Optimal PowerLine system. Thanks to these technologies, there will be a contribution to making sure of the best quality and developing technolo91r of transmission line.

• Journal of Korean Port Research
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• v.15 no.1
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• pp.75-85
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• 2001

Accuracy of dredging processes depends on the types of equipment used, the sediments encountered, whether the work to be performed is new or maintenance dredging, pre- and post-hydrographic surveying and so forth. Among those, position surveying accuracy which is directly determined by the control of the dredge's position and depth surveying accuracy being surveyed at the dredging point during dredging work are important factors. The purpose of this study is to develop 'Dredge Management System'for Grab dredge which is composed of 4 sub-system using LADGPS for dredge position determining system and dredging point determining system, tide gauge system and optical sensor for depth determining system and GIS and ENC for total management system. This system is installed on the grab dredge 'EUNJIN G-18'and applied to anchorage dredging work. at Pohang Harbor. The results revealed that this system is easy to operate, achieves good accuracy with only 45cm unevenness, reduces working period by 22 percent and saves cost 16.6 percent.

• Proceedings of the KSRS Conference
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• 2000.04a
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• pp.61-66
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• 2000

경기만 지역을 대상으로 해안지역 표고자료들의 정확도를 비교 분석하였다. 미국에서 제작한 DTED (Digital Terrain Elevation Model)는 70-80년대에 제작되어 오래되었을 뿐 아니라 약 50 km의 해안선 위치 오차가 발생하기도 하며, 반도가 섬으로 나타나기도 한다. 상용소프트웨어 PCI는 수십 $km^2$에 해당하는 바다를 육지로 생성하였고 해안직역의 표고온차역시 60 m를 초과한다. 지형도를 독취한 수치지도는 지형도 갱신 (10년), 독취에 필요한 시간 (15km $\times$20km에 작업시간만 24일)과 비용, 수동 독취 상의 오차, 측량 난이 지역등의 한계를 가지고 있다. Valadd-pro는 정확한 해안선 정보를 제공하고 해안지역의 표고역시 PCI보다 현실적이다. 경기도 시화호 주변의 4$km^2$ 지역의 등고선은 현지 지형을 현실적으로 보여준다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.24 no.1
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• pp.37-45
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• 2006

Damage of rivers construction is serious to natural disaster by concentration rainfall in summer. Specially, increase of soil erosion breeds flood calamity of river bed accumulation and pondage decline etc., and erosion increase in upper stream shows in rivers flood of earth and sand, farm land and form of urban district burying. Flood damage investigation through on-the-spot probe until present need effective and scientific modelling techniques because is not efficient. This research wished to examine practical use of monitoring data of high resolution satellite image through satellite image analysis of various space resolution. Research analyzed abstraction possibility of soil disaster information using high resolution satellite image. Also, studied soil disaster damage present condition interpretation practical use possibility through various resolution satellite image analysis, and studied practical use of KOMPSAT image for interpretation of river topography change analysis.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.25 no.6_2
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• pp.587-597
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• 2007

This study determines matching size for digital elevation model (DEM) production according to land cover property from IKONOS Geo-level stereo image. We applied area based matching method using correlation coefficient of pixel brightness value between the two images. After matching line (where "matching line" implies straight line that is approximated to complex non-linear epipolar geometry) is established by exterior orientation parameters to minimize search area, the matching is carried out based on this line. The experiment is performed according to land cover property, which is divided off into four areas (water, urban land, forest land and agricultural land). In each of the test areas, matching size is selected using a correlation-coefficient image and parallax image. As the results, optimum matching size of the images was selected as $81{\times}81$ pixels window, $21{\times}21$ pixels window, $119{\times}119$ pixels window and $51{\times}51$ pixels window in the water area, urban land, forest land and agricultural land, respectively.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.33 no.1
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• pp.23-30
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• 2015

A shoreline mapping is essential for describing coastal areas, estimating coastal erosions and managing coastal properties. This study has planned to map the 3D shorelines with the airborne LiDAR(Light Detection and Ranging) data and the KOMPSAT-2 imagery, acquired in Uljin, Korea. Following to the study, the DSM(Digital Surface Model) is generated firstly with the given LiDAR data, while the NDWI(Normalized Difference Water Index) imagery is generated by the given KOMPSAT-2 imagery. The classification method is employed to generate water and land clusters from the NDWI imagery, as the 2D shorelines are selected from the boundaries between the two clusters. Lastly, the 3D shorelines are constructed by adding the elevation information obtained from the DSM into the generated 2D shorelines. As a result, the constructed 3D shorelines have had 0.90m horizontal accuracy and 0.10m vertical accuracy. This statistical results could be concluded in that the generated 3D shorelines shows the relatively high accuracy on classified water and land surfaces, but relatively low accuracies on unclassified water and land surfaces.

• Korean Journal of Remote Sensing
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• v.29 no.5
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• pp.477-486
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• 2013

To analyze tendency of temporal and spatial change of shorelines and to estimate rate of shoreline changes using long-term shoreline change data is very important for the coastal environmental management. In this study, investigation was conducted to estimate the rate of shoreline changes using long-term shoreline change data from the year 1985 to 2009 aerial photographs. In this process aerial triangulation, GPS surveying and digital mapping was done for the estimation of changes. As the results, shorelines of Bangpo and Kkotji Beach retreated at a maximum rate of 0.2 m/yr and 0.8 m/yr, respectively. The shoreline could be changed by various factors. However, it was presumed that coastal erosion has been mainly affected by retaining wall constructed in the late 1990s.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.29 no.5
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• pp.459-469
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• 2011

There are various factors for determining object shape, such as size, slope and its direction, curvature, length, surface, angles between lines or planes, distribution of the model key points, and so on. Most of the object description and recognition methods are for the 2D space not for the 3D object space where the objects actually exist. In this study, 3D chain code operator, which is basically extension of 2D chain code, was proposed for object description and analysis in 3D space. Results show that the sequence of the 3D chain codes could be basis of a top-down approach for object recognition and modeling. In addition, the proposed method could be applicable to segment point cloud data such as LiDAR data.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.30 no.4
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• pp.353-362
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• 2012

3D building modeling from airborne Lidar without model regularization may cause positional errors or topological inconsistency in building models. Regularization of 3D building models, on the other hand, restricts the types of models which can be reconstructed. To resolve these issues, this paper modelled 3D buildings from airborne Lidar by building model regularization which considers more various types of buildings. Building points are first segmented into roof planes by clustering in feature space and segmentation in object space. Then, 3D building models are reconstructed by consecutive adjustment of planes, lines, and points to satisfy parallelism, symmetry, and consistency between model components. The experimental results demonstrated that the method could make more various types of 3d building models with regularity. The effects of regularization on the positional accuracies of models were also analyzed quantitatively.